The Marmot Helium EQ 15° Sleeping Bag let you sleep well—absolutely anywhere. Fiery 850+ goose down meets the weather-fighting power of Marmot’s waterproof and breathable MemBrain® fabric to create a fantastic sleeping system for lightweight travel in unstable alpine climates. Marmot's big mountain heritage is on display from head-to-toe, from the six-baffle hood to the trapezoidal foot box.

I used a Marmot Helium Bag on my through hikes of the PCT ('07) and the CDT ('10) and one of my big concerns, especially on the CDT was that my bag was getting damp/wet at night. I loved the bag so much that I decided to get the Helium Membrane bag to alleviate problems with the bag getting wet. I've used my new bag a few times and I love it. The real test will come after several months on the trail, but so far so good. I think Marmot makes a great bag.

Much roomier than I thought it could be for a 15F down bag -- very lofty and warm. Plenty of elbow room and knee space for side sleepers. I was exposed to 20F temps three nights in a row, and went to bed warm... Even when I noticed I was getting a bit hot in the bag, it never got damp or clammy. Next time I'll try to vent the footbox (there is a two way zipper) and see if that helps even more. The one fault with the bag is the cheesy stuff sack that comes with; while the bag does fit, the material is too light to take constant re-use; both my wife & I's stuff sacks tore at the top within 7 nights of use. Beyond that, this is the best bag I've owned. GO Marmot!